Integrated circuit structures are small electronic components that are fabricated and integrated in a semiconductor wafer. Using a variety of fabrication operations, the integrated circuit structures are made and connected to form integrated circuits on the semiconductor wafer. The integrated circuits are capable of performing functions in operations of an electronic device.
In the electronic device, it is often desired to produce a semiconductor chip with various integrated circuit structures (e.g. a core device and an input-output (I/O) device) according to the requirements in processing speed and power. For example, the I/O device may usually need to sustain a high voltage in the operation. However, the leakage current increases with the high voltage operation. Accordingly, improvements in integrated circuit structures and methods for fabricating the integrated circuit structures continue to be sought.